Patents Assigned to Waagner-Biro Aktiengessellschaft
  • Method for delignification of cellulose with oxygen
    Patent number: 4834837
    Abstract: Method and apparatus for delignifying chemical pulp by means of oxygen, in which an aqueous slurry of chemical pulp is formed, then mixed with a caustic agent, followed by contact with a delignifying fluid. Water is drained off the slurry without reduction of pressure and while maintaining temperature following which the resulting slurry is maintained under these temperature and pressure conditions for a discrete period of time. The thus-obtained treated slurry is then washed.
    Type: Grant
    Filed: July 22, 1987
    Date of Patent: May 30, 1989
    Assignees: Waagner-Biro Aktiengessellschaft, Steyrermuhl Papierfabriks-und-Verlags-Aktiengesellschaft
    Inventors: Heinz Loquenz, Siegfried Meissl, Helmut Schweiger, Norbert Meindl, Karl Schwarzl, Anton Hruschka